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Finding Layer "Delete Deltas"

Jimmy Bouma-Holtrop


I'm having an issue with a layer and it reminded me that I'd read somewhere that App Layering saves a ghost or "deleted delta" of old files when they're removed from a layer. 


Here's my issue: I have a new layer I'll call Layer Two, that I'm installing an application into. Everything installs fine, but when I export in as part of my image several of the application's services are not there in the final published image. The services are there in my app layer, but missing from the registry in the final image. 


After much troubleshooting I'm wondering if the issue is that a different layer, Layer One, which used to contain the application (I split it into its own layer) contains "delete deltas"/ghosts of the uninstalled application files and reg keys? So my question is how do I see in Layer One if those old registry keys are still lurking there and would it be possible for that to be overwriting that data from Layer Two in my final image?



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This is based on an image with all the layers in it and Elastic Layering set to none, disabled.

No, old registry data in an older app layer should not impact the use of an app in a newer app layer.


Layer priority is such, that a newer app layer, with a current timestamp will supersede an older app layer, with the exact same data. The "delete deltas", actually delete tokens, should not impact the functionality of a newer app layer. If the old data, tokens are in the Platform Layer, you will need to recreate that layer, without the application that is in the new app layer. The PL has the highest layer priority and will supersede the other layers.


To determine a conflict between layers we recommend building images with a different set of app layers and testing, In your case, I would build a new image template with half of the app layers and the new app layer, Layer Two, test and see if it works. Should it work, add a few more app layers to the same image template, publish and test. Once you determine which app layer(s) appear to conflict with new app layer, then the best course of action is to recreate the older layer(s), without the application in question.


As for seeing the delete token data, that involves mounting the disk of the app layer to a different vm, and loading our RSD hive file. That is not something we recommend customers do or provide an article for to prevent issues. You could open a case and someone can assist, as best possible.

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